Sudan ebolavirus (SUDV) is a severe and often fatal illness that affects humans. It is one of several species within the Ebolavirus genus, known for causing significant disease outbreaks. First identified in southern Sudan in 1976, SUDV continues to be a public health concern due to its high case fatality rate.
Unique Aspects of Sudan Ebolavirus
Sudan ebolavirus is classified under the Ebolavirus genus, which belongs to the Filoviridae family. This genus includes six recognized species, but only four, including SUDV, are known to cause human disease. While it causes a disease that is clinically similar to other ebolaviruses like Zaire ebolavirus, SUDV has distinct genetic characteristics.
SUDV is believed to have a zoonotic origin, with fruit bats of the Pteropodidae family considered natural hosts. The virus can transmit to humans through close contact with infected animals, such as chimpanzees, gorillas, or forest antelopes, typically through their blood or bodily fluids.
How Sudan Ebolavirus Transmits
Sudan ebolavirus primarily spreads through direct contact with the blood, bodily fluids, or organs of infected people or animals. Bodily fluids that can transmit the virus include urine, feces, vomit, saliva, sweat, breast milk, and semen. Transmission can also occur indirectly through contact with surfaces or objects that have been contaminated with these fluids.
Human-to-human transmission is a significant factor in outbreaks, often occurring through direct contact with a sick or deceased person. Healthcare settings can pose a particular risk if proper infection control measures are not strictly followed. Individuals participating in burial ceremonies involving direct contact with the body of a person who has died from the disease are also at increased risk.
Identifying Sudan Ebolavirus Infection
The incubation period for Sudan ebolavirus, the time from infection to symptom onset, typically ranges from 2 to 21 days. Early symptoms can be non-specific, making diagnosis challenging, and may include sudden onset of fever, fatigue, muscle pain, headaches, and a sore throat. As the disease progresses, more severe symptoms can appear, such as vomiting, diarrhea, a rash, and impaired kidney and liver function. Hemorrhagic manifestations, like bleeding from puncture sites or internal bleeding, can also occur in severe cases, though they are less frequent and may appear later in the disease course.
Diagnosis of acute infection is primarily achieved by detecting SUDV using reverse transcription-polymerase chain reaction (RT-PCR) in blood specimens. This method is effective as viral levels in the blood usually become high within the first few days of symptoms.
Medical Care and Prevention Strategies
Medical care for Sudan ebolavirus infection primarily focuses on supportive measures to manage symptoms and complications. This includes maintaining fluid and electrolyte balance, supporting oxygen status, and managing blood pressure. Treating any secondary infections that may arise is also an important part of patient care. While specific treatments for SUDV are under investigation, some monoclonal antibody therapies have shown promise in animal studies, with certain combinations providing protection against Sudan virus in guinea pigs. Currently, there are no licensed vaccines or specific therapeutics approved for the prevention or treatment of Sudan virus disease.
Prevention strategies involve a combination of public health interventions and individual practices. Strict infection control measures in healthcare settings, including hand hygiene and the appropriate use of personal protective equipment, are important to limit transmission. Safe and dignified burial practices for those who have died from the disease are also important to prevent further spread. Community engagement and awareness campaigns play a significant role in encouraging adherence to prevention guidelines and fostering cooperation during outbreaks. Efforts are underway to develop Sudan ebolavirus vaccines, with some candidates, such as a modified vaccinia Ankara virus producing Sudan virus-like particles, showing effectiveness in animal models.
Significant Sudan Ebolavirus Outbreaks
Sudan ebolavirus has been responsible for multiple outbreaks, primarily in Uganda and Sudan, since its initial identification in 1976. Subsequent notable outbreaks include the one in Gulu, Uganda, in 2000-2001, which reported 425 confirmed cases and 224 deaths.
SUDV has caused eight outbreaks in humans prior to recent events, with five occurring in Uganda and three in Sudan. The virus has emerged periodically, highlighting its continued presence in animal reservoirs in the region. Recent outbreaks, such as those declared in Uganda in September 2022 and January 2025, underscore the ongoing threat and the importance of preparedness and response efforts.